"Simon Riggs" <[EMAIL PROTECTED]> writes: > On Fri, 2007-04-13 at 10:36 -0400, Tom Lane wrote: >> That's what bothers me about this patch, too. It will be increasing >> the cost of writing WAL (more data -> more CRC computation and more >> I/O, not to mention more contention for the WAL locks) which translates >> directly to a server slowdown.
> I don't really understand this concern. The real objection is that a patch that's alleged to make WAL smaller actually does the exact opposite. Now maybe you can buy that back downstream of the archiver --- after yet more added-on processing --- but it still seems that there's a fundamental misdesign here. > Koichi-san has included a parameter setting that would prevent any > change at all in the way WAL is written. It bothers me that we'd need to have such a switch. That's just another way to shoot yourself in the foot, either by not enabling it (in which case applying pg_compresslog as it stands would actively break your WAL), or by enabling it when you weren't actually going to use pg_compresslog (because you misunderstood the documentation to imply that it'd make your WAL smaller by itself). What I want to see is a patch that doesn't bloat WAL at all and therefore doesn't need a switch. I think Andreas is correct to complain that it should be done that way. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match